iGo Charger with 4 AA Batteries

This product (iGogreen Green Energy Battery Charger Rechargeable Alkaline Batteries) contains an 'iGo green' 4-slot AA/AAA charger, plus four 'iGo' rechargeable alkaline AA batteries. There are several aspects I like about the iGo charger: 1. It is capable of charging both NiMH and RAM (rechargeable alkaline manganese) batteries. Most chargers are designed for NiMH only and cannot handle RAM batteries. 2. It is 'smart' in that it monitors the voltage of battery in each slot, and stops charging when the battery voltage is high enough (approximately 1.4V for NiMH, 1.6V for RAM) 3. It has individual indicator light for each slot. The green light blinks while charging, and stays on when done. 4. It has a slim one-piece design with a folding AC plug 5. It work from universal voltage of 100-240V AC The only problem with this charger is that it is very slow. The user manual says charging current is 200mA for NiMH, 150mA for alkaline. But the actual charging current I measured drops as battery voltage gets higher, to around 170mA for NiMH, 130mA for alkaline. That means: - To recharge NiMH cells with 2000mAh capacity (such as the Sanyo eneloop AA), it will take about 12 hours. - To recharge alkaline cells with 2000mAh capacity (such as the IGO AC05058-0001), it will take about 15 hours Provided that you always keep a spare set of batteries as standby, the long charge time is not a real problem. But if you have a large collection of rechargeable batteries and often need to recharge in a hurry, then definitely look for a charger that can recharge in 2-5 hours. By the way, avoid chargers that advertise less than one hour charge time, since they are bad for battery lifespan. Between 2 and 5 hours, the impact in lifespan is negligible. The iGo rechargeable alkaline batteries have the same chemistry as single-use alklaine batteries. So it has the same voltage of 1.5V (instead of just 1.25V for NiMH type). They are advertised to have a capacity of '2000mAh', but that is ony possible when delivering a very low current of around 25mA at room temperature. At high current or at lower temperature, the capacity drops significantly. This is because iGo cells inherited the same limitations as alkaline cells: high internal resistance, and poor low-temperature performance. I measured capacities of iGo cells using my La Crosse BC1000 (at 100mA down to 0.9V), and only observed an average of 1628mAh during the first discharge. Worst yet, the capacity drops quickly with each recharge/discharge cycle: - After just one recharge (using the iGo charger), the average capacity dropped by 19% to just 1316mAh - After two more recharge/discharge cycles, the average capacity dropped further by 4%, to 1255mAh Based on the above trend, I estimate the average capacity of iGo cells will fall below 814mAh (50% of initial value) after another 15 discharge/recharge cycles. That means a lifespan of around 20 cycles. In contrast, Sanyo claims 2nd-gen eneloop cell can last for 1500 deep discharge/recharge cycles, before its capacity drops below 50%. I have many first-gen eneloop cells bought 7 years ago, and they are still working just fine. All things considered, this package is a good deal just for the iGo smart charger. The four iGo rechargeable alkaline batteries can still be useful in low-drain appliances, such as wireless mouse and keyboard.